This invention generally relates to cosmetic products having deodorant and antiperspirant activities. More specifically this invention relates to nonaqueous aerosol deodorant-antiperspirant compositions having a bicarbonate salt content.
Sodium bicarbonate long has been recognized for its deodorant properties, and has commonly been used as a household deodorant. Plain powdered sodium bicarbonate, or sodium bicarbonate diluted with talc or other filler, has been used as an underarm deodorant as disclosed in U.S. Pat. No. 4,382,079. Other publications which describe cosmetic stick compositions containing a bicarbonate deodorant include U.S. Pat. No. 4,822,602 and U.S. Pat. No. 4,832,945.
However, the development of a practical and effective composition in cosmetic product form which has a deodorization capacity, and which is capable of consumer acceptability, presents many factors which are unique. Because sodium and potassium bicarbonate have only limited solubility in water, alcohol and other solvents, the preparation of a composition suitable for dispensing in cosmetic product form has involved many processing obstacles. In addition to the problem of limited solubility, sodium bicarbonate often is incompatible with other ingredients of conventional cosmetic formulations.
Other limiting factors are described in references such as U.S. Pat. No. 4,534,962. Sodium bicarbonate in solution undergoes persistent degradation into carbon dioxide and sodium carbonate (a known skin irritant). Because alkali metal bicarbonate has solubility limitations, a proportionally larger amount of water is required for higher bicarbonate salt levels in cosmetic products. Consequently less alcohol is permitted, which results in a cool wet feel on skin, and slow drying of an applied cosmetic product.
Other product developments include aerosol suspensions which are sprayed from a pressurized container having a content of particulate sodium bicarbonate slurried with a liquid propellant medium. Alkali metal bicarbonate in a propellant-soluble vehicle such as ethanol (0.3-15 weight percent) with about 90% propellant is described in British Patent 1,476,117.
The difficulties encountered with aerosol suspensions of sodium or potassium bicarbonate include the settling and/or agglomeration of the particulate suspension phase, clogging of the dispensing nozzle, a non-uniform spray pattern, nonadherence of the particulate bicarbonate deodorant to the sprayed skin area, and an overly wet spray which requires an extended drying time.
Other cosmetic products have been developed which exhibit antiperspirant activity against underarm wetness in human subjects. An antiperspirant is applied to suppress perspiration and prevent offensive odors such as an axillary odor caused by decomposition of sweat. A popular type of antiperspirant cosmetic product is a nonaqueous aerosol formulation which contains an antiperspirant-active ingredient such as aluminum chlorohydrate, a carrier such as talc, an oil component to deposit and retain the antiperspirant-active ingredient on a skin surface, and a liquid propellant medium. One disadvantage of nonaqueous aerosol antiperspirant products is the tendency for dust cloud formation which the aerosol medium is dispensed from a pressurized container.
There is continuing interest in the development of cosmetic products which have a high level of consumer acceptance.
Accordingly, it is an object of this invention to provide an improved cosmetic product which is composed of a nonaqueous liquid medium having effective quantities of deodorant-active and antiperspirant-active ingredients.
It is another object of this invention to provide an aerosol deodorant-antiperspirant composition which is a liquid solution of organic ingredients and propellant medium, and which has a dimensionally stable suspension phase of particulate alkali metal bicarbonate ingredient and particulate antiperspirant salt ingredient.
Other objects and advantages of the present invention shall become apparent from the accompanying description and examples.